Herbarium factsheet

What is an herbarium?

An herbarium (plural: herbaria) is an institution housing a collection of preserved plants that have been gathered and classified over a long period of time. An herbarium also stores records regarding these plants.

Why are herbaria important?

Herbaria are used to study the relationships among plant species, to study how plants evolved over time and to document the plants of an area. They are very useful in helping to determine the identity of unknown plants or discovering new species. Many herbaria contain specimens of local plant life, recording the region’s flora.

What is an herbarium press?

An herbarium press is a wooden device that is used to flatten plant specimens.

How to make an herbarium press

What you need

• two wooden grids, 12 x 18 inches (30.5 x 46 centimetres) each
• two straps or ropes that can be easily tightened (or two vice clamps)
• pieces of corrugated cardboard (12 x 18 inches / 30.5 x 46 centimetres), one piece of cardboard for each specimen plus one extra.
• sheets of standard-size newspaper (24 x 36 inches / 61 x 91.5 centimetres), one sheet for each specimen.

What to do

Watch the animation: Making an herbarium specimen (Flash SWF, 1.13 MB)

An herbarium press is a “plant specimen sandwich.” Here's how to make one:

1. Place one wooden grid on a flat surface.
2. Add one piece of corrugated cardboard.
3. Prepare the plant specimen for drying: Place the specimen on half of a newspaper sheet. Make sure that the important features of the plant are visible, including flowers. Carefully fold the other half of the sheet onto the specimen.
4. Place the specimen on the cardboard.
5. Cover the specimen with another sheet of cardboard.
6. Repeat steps 3 to 5 until all specimens are pressed.
7. Add the second wooden grid on top of the stack of specimens.
8. Bind the press with the straps, ropes or vice clamps. Avoid binding in the centre of the press. Tighten firmly.
9. Keep the herbarium press in a warm and dry environment to prevent mould development.
10. Check your specimen every day to make sure it is drying in the right position. If it is not, you can make adjustments when the plant is not yet fully dry.

What parts of the plant to collect

The perfect plant sample shows as many of the plant’s identifying characteristics as possible: flowers, leaves, bark, fruits, roots and so on. Depending on the species, you may need to collect as much as the entire plant or as little as a branch with flowers or fruits. (If possible, collect both the flowers and the fruits!) The collected material should be compact enough to fit within a 30-centimetre by 45-centimetre (12-inch by 18-inch) herbarium press.

How to make a capsule

Watch the animation: Making a capsule (Flash SWF)

To store small parts of a plant specimen, such as seeds and leaves that have fallen off or have been removed, you can use a capsule, a folded sheet of acid-free paper that attaches to the mounting sheet. The capsule provides easy access to the material and keeps it with the specimen. Acid-free paper prevents damage to the plant parts.

Mounting the pressed specimen

• Use a long-lasting, non-acidic mounting tape.
• Lay out the specimen so that it shows its best qualities and most important features.
• Make sure it fits on the 12- by 18-inch (30.5- by 46-centimetre) mounting sheet. (If it is slightly too big, place it diagonally on the sheet.)
• Leave enough room in the bottom right-hand corner for the label as well as the capsule, if necessary.

How to label a specimen

The label should include the following

1. herbarium name
2. family of the plant specimen
3. herbarium accession number
4. species name, in as much detail as possible
5. plant accession number (optional)
6. location — a detailed description of where you found the plant
7. altitude— the altitude of the location in which you found the plant
8. latitude and longitude — the exact location of where you found the plant
9. habitat
10. collector’s name
11. determined by — the name of the person who identified the specimen
12. collector’s number
13. date planted, if known
14. collection date

Your label should be approximately the same size as this sample. You may leave out any sections your herbarium does not require. The most important sections are the species name, location, habitat, collector and collection date.